# AoC2015
Advent of Code 2015 in Kotlin, done at a slow pace in 2022

This is done together with a few friends and colleagues who want to use the AoC problems
to improve their coding proficiency. In my case, I am using these problems to practice
Kotlin while I learn it.

A remark on Kotlin for each "day":
- 01: ~when()~ control structure (or expression) is nice to have -- also appeared in python 3.10
- 02: *extensions functions* combine well with a "functional programming" style
- 03: *companion object* is Kotlin's way of grouping "constant" or "static" members of a class
- 04: single-line ~fun~ definitions with ~=~ and expression ~if~ may help with short, readable code
- 05: maybe extension functions should be scope-restricted to avoid accidental misuse?
- 06: during class inheritance, explicit use of the ~override~ keyword is mandatory
- 07: testing for ~null~ can be chained with "elvis operators"
- 08: beware of ~Regex~ expressions containing backslashes or double quotes, even in "raw" strings
- 09: /nullability/ checks matter, notably for map elements! (and can cause headaches when absent...)